Six Nato soldiers have died in the latest attack on forces serving in Afghanistan

A rogue Afghan policeman has shot dead six Nato troops before being killed himself.

The shooting - the highest toll for Nato forces since nine Americans died in a September helicopter crash - was the latest in a series in which Afghan security forces have turned on their Nato partners.

The Afghan Interior Ministry confirmed that the gunman was a border police officer, rather than an insurgent disguised to infiltrate government forces.

The incident happened in Pachir Wagam district of Nangarhar province - right on the border with Pakistan.

Nato declined to identify the nationalities of the victims, but the majority of forces in Nangarhar are American.

There have been several incidents in which Afghan police officers turned on their trainers. Nato is investigating one in which two US Marines were killed earlier this month in southern Helmand province at the hands of an Afghan army soldier.

On July 20, an Afghan army sergeant got into an argument at a shooting range in northern Afghanistan and shot dead two American civilian trainers before being killed. Another Afghan soldier was killed in the crossfire.

In a July 13 attack, an Afghan soldier stationed in the south killed three British soldiers, including the company commander, with gunfire and a rocket-propelled grenade in the middle of the night.

And in November 2009, an Afghan policeman killed five British soldiers at a checkpoint in Helmand. A month earlier, an Afghan policeman on patrol with US soldiers fired on the Americans, killing two.